XObject.Annotations<T> Method

public IEnumerable<T> Annotations<T>()
where T : class

public class MyAnnotation {
    private string tag;
    public string Tag {get{return tag;} set{tag=value;}}
    public MyAnnotation(string tag) {
        this.tag = tag;
    }
}

class Program {
    static void Main(string[] args) {   
        XElement root = new XElement("Root", "content");
        root.AddAnnotation(new MyAnnotation("T1"));
        root.AddAnnotation(new MyAnnotation("T2"));
        root.AddAnnotation("abc");
        root.AddAnnotation("def");

        IEnumerable<MyAnnotation> annotationList;
        annotationList = root.Annotations<MyAnnotation>();
        foreach (MyAnnotation ma in annotationList)
            Console.WriteLine(ma.Tag);
        Console.WriteLine("----");

        IEnumerable<string> stringAnnotationList;
        stringAnnotationList = root.Annotations<string>();
        foreach (string str in stringAnnotationList)
            Console.WriteLine(str);
    }
}

T1
T2
----
abc
def